U-tube heat exchangers, which is a heat exchanger provided with an outer cylinder, a tube plate that divides an inside of the outer cylinder into a first end side tube-interior fluid chamber and a second end side tube-exterior fluid chamber, and a plurality of U-tubes disposed inside the tube-exterior fluid chamber and having both ends thereof fixed to the tube plate.
One example of such a U-tube heat exchanger is disclosed in Patent Document 1, for example. The tube-exterior fluid chamber of this U-tube heat exchanger is provided with a partition wall that divides the tube-exterior fluid chamber into a first straight-tube chamber including inlet-side straight-tube sections of the U-tubes, and a second straight-tube chamber including outlet-side straight-tube sections of the U-tubes. Furthermore, the first straight-tube chamber and second straight-tube chamber are provided with a plurality of baffles. In this U-tube heat exchanger, a tube-exterior fluid is also caused to flow in a region where curved-tube sections of the U-tubes exist, or in other words, an end plate region on the inner side of an end plate of an outer cylinder, in order to increase the heat transfer area between a tube-interior fluid flowing inside the U-tubes and the tube-exterior fluid flowing outside the U-tubes.